Lamination stacking arrangements



LAMINATION smcxmc ARRANGEMENTS Filed May 17.1954

mmvron DANIEL J. SIKORRA ATTORNEY United States Patent LAMINATIONSTACKING ARRANGEMENTS Daniel J. Sikorra, Champlain, Minn., assignor toMinneapolis-Honeywell Regulator Company, Minneapolis, Minn., acorporation of Delaware Application May 17, 1954, Serial No. 430,194 4Claims. (Cl. 336-217) The present invention relates to laminated,magnetic core structures and more particularly to improvements in theirease of magnetization by the arrangement or stacking of the laminationsand by the relation of the laminations to the oriented grain structureof the material from which they are fabricated.

In core constructions currently in use, for such devices as magneticamplifiers or very high primary reactance transformers, undesirableeffects have been caused by the air gaps between abutted laminations andby the inefficient use of the oriented grain structure of the laminationmaterial. The improved structure herein disclosed provides a core whichovercomes the use of abutted air gaps in its magnetic circuit and allowsgreater ease of magnetization of the oriented grain structure of thecore. The magnetic core is formed of a novel stacking of conventionalEand I or E and square laminations, where square refers to any laminationof a square or rectangular shape with an open center or window area. Themembers of the laminations may be of any desired proportions and are notrestricted to those shown.

It is an object of this invention to provide a laminated core formed ofconventional laminations, and having a greater ease of magnetizationthan conventional cores.

It is another object of this invention so provide an improved,laminated,'magnetic core structure in'which the oriented grain structureand magnetic circuit are gen erally in the same direction.

It is also the object of this invention to provide an improved corestacking to permit a magnetic circuit to be formed which, for practicalpurposes, eliminates the necessity of the flux crossing through anabutted air gap.

These and other objects of this invention will become apparent from thereading of the attached specification together with the drawing wherein:

Figure 1 is an exploded view of an arrangement of E and I laminations:

Figure 2 is an exploded view of an arrangement of E and square shapedlaminations;

Figure 3 is a side view of a core formed of laminations shown in Figure1 and having a coil on the center leg of the core.

The laminated, magnetic core structure of the subject invention, as isshown in one form in Figure 1, is made of laminations in the form of anE 10 and laminations in the form of an I 11. The E 10 and I 11laminations are formed of a magnetic material which is produced to havean oriented grain structure in the direction of the arrow 13. The Ilaminations 11 are abutted to the heels 14 of the E laminations 10 sothat the oriented grain structure indicated by arrows 13 in the Elaminations 10 are at right angles to the oriented grain structure inthe I laminations 11. The combination of E 10 and I 11 laminations arealternately stacked so that the I laminations 11 of a layer overlay theends of the legs 15 and 16 of the E laminations 10 in adjacent layers.

In the core structure disclosed above, a typical magnetic circuitfollows two paths and neither path crosses through the air gaps betweenthe heels 14 of the E laminations 10 and the associated I laminations11. The two paths followed by the flux in the improved coreconstruction, for example, would be as follows:

The first path for flux originating in the center leg 16 of an Elamination 10 would be to follow the oriented grain structure in thedirection of arrow 13 in leg 16 until it reached the heel 14 which isintegral with its leg 16, then divide and move crossgrain in theintegral heel 14 until reaching legs 15. At legs 15 the flux would againflow along the legs 15 in the direction of the oriented grain structureindicated by the arrow 13 until reaching the end area of legs 15. Fromthe end area of legs 15 the flux flows to adjacent I laminations 11through lapped joints, then in the adjacent I laminations 11 in thedirection of the oriented grain structure indicated by arrow 13. Whenthe flux reaches the lapped area between the I lamination 11 and the leg16 in which it originated, it returns through the lapped area betweenthem to complete its circuit.

The second path for flux originating in the center leg 16 of the Elamination 10 would follow the oriented grain structure in the directionof the arrow 13 in leg 16 until it reached the heel 14 which is integralwith its leg 16, then flow through lapped joints to the legs 16 adjacentto it, through the lapped joints to the I lamination 11 in its originallevel. Upon reaching the I lamination 11 the flux would flow in theoriented grain structure in the direction of arrow 13 and return to legs15 through lapped joints and complete its circuit as described above.

From the above description of fiux paths, it can be seen that at no timeis the flux required to flow through the abutted air gaps between E 10and I 11 laminations, and that flux flow is generally in the directionof the oriented grain structure of the core.

This invention is not limited to the specific configuration shown inFigure 1. Figure 2 shows another core construction utilizing thisinvention, and which contains alternately stacked E laminations 10 andsquare laminations 12, where square refers to any lamination of squareor rectangular shape with'an open center or window area. In thiscombination a typical flux path is through the center leg 16 of the Elamination 10, lapped joints from leg 16 to leg 21 of the squarelamination 12, through leg 21 and lapped joints to legs 15 of the Elamination 10 of its original layer, through lapped joints from legs 15to leg 20 of the square lamination 12 and back through lapped jointsbetween leg 20 and leg 16 of the E lamination 10. It can be readily seenfrom Figure 2 that this path follows the oriented grain structureindicated by arrows 13 in all legs and that no abutted air gaps arepresent. The stacking disclosed in Figure 2 provides for a core whichcontains only 50 percent as many laminations in the center leg 16 as inthe outside legs 15 in combination with the square laminations 12. Thisarrangement is advantageous in certain core applications.

As shown in Figure 3 the laminations can be stacked with relation to aprewound coil or coils 22, with leads 23, in a conventional manner. Itis understood that coils may be arranged on the core structure on anyleg or in any number desired. The laminations may be held in place byany convenient means such as a clamp, nuts and bolts, or such meansfamiliar to those versed in the art. Since the abutted air gaps betweenE laminations 10 and I laminations 11 do not enter the magnetic circuit,their spacing is less critical than in conventional types of stackmg.

In general, the arrangements of laminations in Figures 1 and 2 can befabricated rapidly, economically, rigidly 3 and have a greater ease ofmagnetization than conven tional cores using the same core material.

In considering this invention it should be kept in mind that thisdisclosure isintended to be illustrative only and the scope of theinvention is to be determined by the appended claims.

I claim as my invention:

1. In a magnetic core, a plurality of layers of laminations withoriented grain structure, each alternate layer having at least a firsttype of member and each other alternate layer having at least a secondtype of member, the first type of member having a plurality of legsintegral at one end only with a transversely extending heel portionjoining said legs at said one end, said legs being unconnected at theiropposite ends and the oriented grain structure being parallel to saidlegs, the second type member including a rectangular portion of the samelength as said heel portion and having the grain structure extendinglongitudinally thereof, said layers being stacked with the rectangularportion of said second member over- 0 lapping the unconnected ends ofthe legs of the members of said first type in adjacent layers to providea magnetic circuit between said legs through said rectangular portionsin the direction of grain orientation.

2. In a magnetic core, a plurality of layers of laminations withoriented grain structure, each layer comprising a first type of memberand a second type of member, the first type of member having a pluralityof parallel legs integral at one end only with a transversely extendingheel portion joining said legs at said one end, said legs beingunconnected at their opposite ends and the oriented grain structurebeing parallel to said legs, the second type of member being I-shapedand having the grain structure extending longitudinally thereof, saidsecond type of member being disposed in each layer adjacent to andparallel With the heel member of said first type of member, said layersof laminations being so stacked that the legs of said members of thesecond type overlap the unconnected ends of the members of said firsttype in adjacent layers to provide a magnetic circuit between said legsthrough said members of the second type in the direction of grainorientation.

3. In a magnetic core, a plurality of layers of laminations withoriented grain structure, each layer comprising an E-shaped member andan I-shaped member, the

E-shaped member having three parallel legs integral at one end only witha transversely extending heel portion joining said legs at said one end,said legs being unconnected at their opposite ends and the orientedgrain structure being parallel to said legs, said I-shaped member havingthe grain structure extending longitudinally thereof, said I-shapedmember being disposed in each layer adjacent to and parallel with theheel member of said E-shaped member, said layers of laminations being sostacked that the I-shaped members overlap the unconnected end of thelegs of said E-shaped members in adjacent layers to provide a magneticcircuit between said legs through said I-shaped members in the directionof grain orientation.

4. In a magnetic core, a plurality of layers of laminations withoriented grain structure, each alternate layer having at least a firsttype of member and each other alternate layer having at least a secondtype of member, the first type of member having a plurality of legsintegral at one end only With a transversely extending heel portionjoining said legs at said one end, said legs being unconnected at theiropposite ends and the oriented grain structure being parallel to saidlegs, the second type of member being in the form of a frame havingopposite rectangular portions of the same length as said heel portionand having the grain structure extending longitudinally of saidrectangular portions, said layers being stacked with one of therectangular portions of each of said second members overlapping theunconnected ends of the legs of said members of said first type inadjacent layers to provide a magnetic circuit between said legs throughsaid one of said rectangular portions in the direction of grainorientation.

References Cited in the file of this patent UNITED STATES PATENTS428,575 Stanley May 20, 1890 FOREIGN PATENTS 618,114 Great Britain Feb.16, 1949 151,310 Australia July 26, 1951 693,288 Great Britain June 24,1953 291,922 Switzerland Oct. 1, 1953 1,054,551 France Feb. 11, 1954

